Flask-closing apparatus for vulcanizers.



G. B. SNOW. FLASK CLOSING APPARATUS FOR VULGANIZERS.

APPLICATION'FILED JUNE 22,1911- Patented Jan. 29,1918,

9 F j 4 i 22 z Z 2o 2 7 Figl GEORGE BURWELL SNOW, OF LONG BEACH, CALIFORNIA.

FLASK-CLOSING APPARATUS FOR VULCANIZERS.

Specification of Letters Patent.

Application filed June 22, 1917. Serial No. 176,377.

To all whom it may concern:

Be it known that I, GEORGE BURWELL Snow, of the city of Long Beach, in the county of Los Angeles and State of California, a citizen of the United States, have invented certain new and useful Improvements in Flask-Closing Apparatus for Vulcanizers, of which the following is a'specification.

This invention relates to a form of apparatus used with vulcanizers, by means of which the flask which contains the piece to be vulcanized may be closed after it has been placed in the vulcanizer, and at any time during the vulcanizing process that the operator may choose for so doing. It consists in the addition of springs to the apparatus, placing them outside the vulcanizer instead of inside, as they have heretofore been placed, and in such a manner that the pressure exerted by the said springs upon the flask may be accurately known and gaged. It also consists in placing ribs upon the lower surface of the vulcanizer cover, to afford a free circulation of steam around the flask, so that it will be evenly heated.

In the accompanying drawing, Figure 1 shows an elevation of a vulcanizer to which my device has been applied; one half there of being shown in a Vertical diametral section. 1 Fig. 2 represents a plan of the lower side of the cover of the said vulcanizer.

Fig. 3 is an elevation of the cap nut 3 on an enlarged scale, showing the graduations by means of which the amount of pressure may be ascertained which is exerted upon the flask to close it.

Like reference numerals refer to like parts in all the figures.

In Fig. 1, 16 represents the upper part of a vulcanizer pot, and 19 the cover thereof; 17, a platform situated inside the vulcanizer upon which a flask or flasks may be placed,

and closed by being drawn upward against the lower side of. the vulcanizer cover 21 by means of the rods 2-2, the cross-head 1, and the central actuating screw 5. The passage of the rods through the vulcanizer cover is rendered steam-tight by means of the stuffing boxes 20. A chamber is bored out in each end of the crosshead 1 for the reception of a spiral spring, one of which is shown at 4. The rod 2 passes through a hole 22 in the bottom of the said chamber, the rod being reduced in size for the purpose of limiting Patented Jan. 29, 1918.

its upward movement through the said hole I 22. The upper end of the rod 2 is threaded for the attachment of thecap nut .3, which passes freely into the cham'bei; which receives the spring 1, and forms an abutment for the said spring. The cap nut 3 is suitably graduated upon its side to show the amount of pressure exerted upon the flask by the spring 4, as shown at 9 Fig. 3. As the actuating screw 5 should operate the crosshead 1 in either direction, upward or down-' ward, its lower end passes into a pocket 29 in the cover 19, and is provided with a collar 7, secured by a cross-pin 8; which collar is held against the cover by the bushing 6. The actuating screw 5 is thus permitted free rotatory movement, but is prevented from moving vertically. i e

. The conversion of the compound of caoutchouc and sulfur into vulcanite is attended with an increase in the specific grav ity of the mass, and a consequent diminution or shrinkage in its bulk; and Letters Patent .were issued to your applicant bearing date June, 1891, and numbered 454,079, for a method of overcoming the effects of the said shrinkage. This method, being adapted for use with ordinaryvulcanizers,could not always be used successfully except by opening the vulcanizer and readjusting the flask when the vulcanizing process was only partially completed; it consisting in the application of spring pressure upon the flask under certain conditions. With the device shown herein, the flask may be closed in the vulcanizer and at any time deemed most expedient by the operator, and without any lnterruption to the vulcanizing process.

It has been ascertained by experiments that to counteract the effects of the shrinkage of the rubber compound in its conversion into vulcanite, about five per cent. more of it should be used than can be contained in the mold in which the piece is to be produced. Consequently, the flask should not be entirely closed when it is placed inthe vulcanizer, but should remain open sufliciently to accommodate the required surplus. It has also "been ascertained that the shrinkage of themass of rubber compound under treatment is not uniform throughout the vulcanizing process, but is more rapid at first; the shrinkage being nearly completed during the first half-of the time re quired for thoroughly hardening the compound. Therefore the flask should be nearly, but not completely, closed when it is placed in my improved vulcanizer and brought up against the lower side of the vulcanizer cover by the rotation of the actuating screw 5, so that it is there held with out pressure being applied to close it. The vulcanizcr being closed and heated, and about ten minutes after the vulcanizing temperature has been attained, the actuating screw 5 may be turned to produce a slight pressure upon the flask to close it, and this pressure may be increased as the vulcanizing process continues. The increasing pressure. is obtained by the elevation of the cross-head 1, and the compression of the springs a, between the cross-head l and the cap-nut 3. And as the cross-head is raised by turning the actuating screw 5, it covers the graduations 9 upon the cap-nut 3, one by one, as the pressure is increased; the lowest figure in sight always denoting the pressure attained. As an undue amount of pressure may result in crushing the plaster mold in which the piece is vulcanized, it is a matter of some importance that the operator of the apparatus should know how much pressure he is applying upon the flask.

Referring to Fig. :2, which shows the plan of the lower side of the vulcanizer cover, lour notches 15 are shown in the circumference tor the reception of swing bolts; by means of which the cover is secured to the vulc: nizer pot, holes 18, 18, for the attachment of the stufling boxes 20, a hole 13, for the reception of the mercury bath for the theri'nometer, and other holes 11, 12 and i l for the attachment of the safety apparatus, blow-oft valve and heat regulator. These parts are omi ted from the drawing, as they are well known, and have no bearing upon my invention.

The general contour of the lower surface of the cover is arched or vaulted (see dotted line 523, 1), but to secure level bearing Surface :tor the flask, ribs 10, are added, which extend downward to the line '21, Fig. 1. Then when the cover is surfaced in the lathe, the edges of the ribs will afford a true and suflicient bearing surface for the flask; while steam will be permitted tree passage above it, and it will be heated uni'li'o "mly on all sides; something which would not obtain it the flask were brought up against the flat surface of the cover itself, with no steam space between the two. I

I am aware that flask closing vulcanizers have been constructed in which the flask is raised and pressed against the lower surface oi the cover in much the same manner as herein described, but I am not aware that spring pressure has been a feature in such devices. I am also aware that springs have been interposed between the flask and an actuating screw, by means of which pressure was exerted to close the flask, but in this case the spring 01' springs were situated within the vulcanizer, or an extension of the steam space thereof, and the springs, being exposed to constant moisture, soon lost their elasticity by rusting. But 1 am not aware'that any device has heretofore been produced in which spring pressure has been applied to the flask in a vulcanizer by springs situated outside oi? the steam chamber thereof, nor am I aware that means have heretofore been provided for showing the amount of pressure that is being exerted by the springs upon thefiask to close it.

1 therefore claim as my invention:

1. A- flask closing device for vulcanizers, consisting of a platform situated in the vul. canizaer and suspended on rods passing through the cover thereof, a cross-head, slidably connected to the said rods, springs interposed between the cross-head and the said rods by means of nuts upon the said rods, and a central actuating screw; substantially as described. I r

A flask closing device for vulcanizers, consisting of a platform suspended upon rods passing through the vulcanizer cover, and through pockets formed in the extremities of a cross-head, spiral springsjsituated in the said pockets and encircling the said rods, graduated cap nuts fastened to the ends or the rods for compressing the springs, and a central actuating screw; substantially as described.

3. A vulcanizer cover, ribbed on its lower surface, with the lower and free edges of the ribs situated in a plane, stulflng boxes in the cover, a platform below the cover with sliding rods attached thereto and passing through the said stufling boxes, and a crosshead above the cover and attached to said sliding rods; the whole being operated by a vertical screw having its bearing at the center ,of the cover; substantially as hereinbe'tore set forth;

GEORGE BURW'ELL SNOXV.

Vitnesses VIVIAN M. STnvnNs, R. H. MAsoN.

fiepies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

